When a plant decides how to deal with oil and grease on machinery, floors and handling hardware, the discussion usually starts with cleaning power. On oily surfaces that argument rarely settles anything, because two shops with the same machine and the same detergent can differ by a wide margin in how much water they actually spend. Water becomes the deciding constraint in a growing number of factories: the bay has no drain, the floor must be dry before the next shift walks over it, the oily rinse water has to be collected and handled, or the site draws on a metered supply that someone is being asked to justify. Before you compare methods for those surfaces, work out your own water position.
This article is a working method for measuring and evaluating that position on oil-contaminated surfaces in a plant. It does not start from a flow rate, because published flow rates describe a machine, not your shop. It starts from numbers you can collect in one shift, and it ends with what you should require in writing from any supplier who quotes you after that.
Classify the oil before you choose a method
The same word - oil stain - covers several different jobs, and they consume water at different rates for different reasons. Separate them on your own list before you talk about equipment.
A wet film is fresh cutting or forming fluid that has not dried. It is thin, mobile and comes off with relatively little liquid, provided it has not been spread over a wide area by walking or by a leaking tray.
Aged, tacky residue - the varnish-like film found around gearboxes, way covers and the underside of guarding - has partially oxidised. It no longer behaves like a liquid. It requires dwell time and mechanical action, and attempts to flush it away with volume are the most common way water is wasted on oily surfaces.
A third case is oil holding grit: grinding dust, swarf fines and road or foundry sand bound into the film. Here the risk in a low-water approach is not that the soil will stay, but that the abrasive particles get moved and re-deposited, or scratched into a finished surface while you work. Note this category on your list; it changes what you are willing to accept as a result.
Photograph each case where it occurs, and keep the photographs. Water decisions made from a general impression of "the shop is oily" are revised later at cost.
Measure four numbers you already generate
Do not buy anything, and do not change the method, until you have four readings from a single bay over a single shift, taken with your own people on your own surfaces.
First, gun-on minutes: how long a lance or hose is actually running, not how long the task takes. Second, refill and re-hose events: how many times the operator stops to move a hose, top up a tank or wait for a line to recover. Third, the walk to the nearest water point, and whether that route crosses an aisle. Fourth, the time between finishing and the surface being dry enough to be used again, for a floor or a walkway.
Those four readings tell you more than a metered total on the first pass. Refill stops and hose drag are where hours disappear, and a slow drying surface can cost you production time even when the volume of water looks small. A method that uses less water but leaves a wet floor for longer is not a saving. Record all four together.
Ask what the method does to the water, not only how much it uses
A high-volume wash carries oil off a surface and hands you a large volume of oily liquid to deal with. A low-volume approach loosens the film so that it can be wiped or recovered, and hands you a smaller volume with a higher concentration of oil plus a batch of used wipes. Both are costs, and which one is cheaper depends on your site: whether the bay drains to an interceptor, whether collected oily liquid can leave the site at all, and whether you already pay for wipe disposal.
Write down, for each bay you intend to clean, where liquid is allowed to go today. If there is no drain, then volume reduction changes the problem from "unsolvable" to "manageable", and that fact matters more than the litre figure. If there is an interceptor, note whether it is reachable, in service and sized for the flow you would produce in a single cleaning window - a drain that cannot keep up during the job leaves liquid standing on the floor afterwards.
If your plant handles food or animal feed anywhere near the oily area, add the hygiene requirement to the sheet before water is discussed, so that a low-water method is not judged only on volume. Where both constraints apply, ask specifically about industrial steam cleaning equipment for factory use and ask the supplier to state, in writing, what they expect the water result to be on your photographs rather than on a datasheet.
Choose the mode by the water the floor can tolerate
Machines sold for plant and vehicle work commonly offer more than one delivery mode - drier steam, wetter steam and a hot-water flush - and the mode, not the model, is what drives the water number. A drier mode puts less free liquid on the surface and is the choice where there is no drain, where electrical hardware is nearby, or where the surface must return to service quickly. A wetter mode or a hot-water rinse puts more liquid down and is the practical answer when there is a drain, a sloped floor, and time for the area to dry.
So the question to put to a supplier is not "how many litres per hour" in the abstract, but which mode produces which result on my surfaces, at what nozzle distance and travel speed, and how long the area stays wet afterwards. If the answer is a single number without a mode and a method attached to it, the number cannot be compared with anything and should not be used to choose between quotes.
The PowerDe HW02 steam cleaner page, for example, lists an 80 L SUS304 tank, a tap-water inlet with a half-inch four-point internal-tooth joint, a 6 kW heating load and a 220 V supply. Read those items as installation facts: they tell you how often the tank must be refilled, what water connection the bay needs and what circuit the job draws. They are not a claim that any particular surface in your plant can be cleaned, and they should not be quoted back as one. Use the same discipline with every supplier: ask what the specification answers about your site.
Map the services at each unit before water is discussed
Water use is capped or inflated by the services next to the machine, so survey them unit by unit rather than assuming the shop is uniform. For each cleaning point, record: is there a tap, and does the thread match the inlet fitting that comes with the machine; how far must a hose be pushed over grating, kerbs, thresholds and cable covers; is there a protected 220 V outlet on that position, with a cable route that does not run across a walkway; and how is the tank refilled during a shift without the operator leaving the job.
Also note geometry, because it decides whether a fixed or hand-pushed unit can even reach the surface: door width, turning space, and clearance around the machine being cleaned. A method that cannot be brought to the surface is not a method. If the survey shows that the standard arrangement does not fit, raise a site survey request rather than forcing the standard machine into the space; that is the point at which customized steam cleaning equipment becomes a reasonable question rather than an assumption.
Run one timed trial on your worst surface
Ask for a trial unit, or run the trial with what you already own, on the dirtiest representative area, worked by your own operators inside a window you control. Before the trial, freeze the settings in writing: mode, nozzle and its angle, distance from the surface, travel speed, number of passes, and dwell time. Have the operator sign that sheet. After the trial, measure the same four readings - gun-on minutes, refill stops, walk distance, drying time - and compare them with your own baseline, not with a catalogue figure.
Agree the pass criteria before the trial starts, in checks somebody can verify: a white cloth pulled across the surface shows no film; painted surfaces show no blistering or colour change; sealed housings and cable entries re-checked afterwards show no ingress; the floor is dry enough to walk on within an agreed time. Name the failures that automatically reject the result and the person who signs it. A trial judged by opinion afterwards gets repeated, and the repetition is where the water and the hours go.
Put the cost of keeping the machine in the water account
Hard water changes a low-water method over time. Scale inside heaters and generators drifts output and flow, so the result you measured in month one is not what you get in month ten; the cost moves from water to descaling, part replacement and downtime. This matters most where a site runs on borehole water or on supply known to be hard.
Ask, in the same enquiry that asks about water, what the inlet filter is and where it is, which wear items exist - nozzles, seals, hose and gun ends, filter - with part numbers and lead times, what descaling interval the supplier expects, and what hardness limit they work to. Then name the person on your side who owns descaling and inlet checks, and put that name into the same controlled document that holds the cleaning parameters. A low-water method that is quietly abandoned because nobody owns its upkeep is worse than the old method it replaced.
Be honest about where low water is the wrong answer
Some situations need volume. A large open floor with a working drain and time to dry may be cheaper and faster to flush. Oil loaded with abrasive fines may need a method where the particles are carried away and recovered rather than disturbed and re-deposited. Areas with protected electrical assemblies, junction boxes, lamps, cable chains and breathers close to the surface may need the hardware removed, isolated and locked out first, or the surface cleaned by another route entirely.
Put those exclusions in writing as a no-spray list signed by the equipment owner before any trial, and keep it beside the parameters. It protects the equipment and it prevents a water saving on the floor from turning into a repair bill.
Carry the numbers into the enquiry
When you finally ask for a proposal on oily factory surfaces, do not lead with a model number. Send the surface list, the photographs of the three soil types, the timed record from your current method, the survey facts for each position (tap and fitting, hose route, available protected supply, where liquid may go), and the four baseline readings you measured. Ask the supplier to answer with a frozen set of figures for the setting they propose: mode and nozzle, expected water per hour at that setting, tank capacity and refill interval, inlet fitting and any adapters supplied, the power the unit needs, and a wear-part list with part numbers.
Keep the cleaning parameters themselves - mode, nozzle, distance, passes, dwell - in the same controlled sheet as the water expectation, so that the result is repeatable when the operator who ran the trial is not on shift.
If you want a second opinion on what a low-water method would mean on your own oily surfaces, contact PowerDe with your surface list, photographs and timed record rather than a part number.
A short checklist before you commit
Before any purchase or trial on oil-stained surfaces, you should be holding: the four baseline readings from one bay and one shift; a soil classification with photographs for each case; a signed no-spray list from the equipment owner; a unit-by-unit survey of tap, fitting, hose route, protected supply and permitted drainage; a frozen trial sheet showing mode, nozzle, distance, travel speed, passes and dwell, signed by the operator; a wear-part list with part numbers and lead times, plus the name of the person who owns inlet checks and descaling; and a drying-time comparison against your current method. If any one of those is missing, the water number in front of you is not yet a basis for a decision.
